Psytaco the blotter art you describe could be either of or any thing. I've seen it used for LSD, NBOMe and DOX, DOM, DOC. Some of the ezy test kits detect tryptamines. There is a local product that contains 5 reagent kits, plus comes in big bottles, therefore reusable many, many times. Cost the same as 3 single use ezy tesy kits.
Of topic. Potency? Well if stored in airtight container in a cool, dark place should be fine, maybe a tiny amount loss of potency but not significant. That is if it is LSD. NBOMe no worries there, it won't oxidize like LSD. DOC, DOB etc also stable compounds vs LSD.
My point: blotter art is kind of meaningless. Imported LSD comes in laid/then is laid on tabs with a certain image, people buy it and rate it. Some bloke has some NBOME lays tabs with the same print, probably printed at home from the net.
The difference is LSD has no smell or taste. Everything else (except analogues like ald 52, lsz which give different subjective experience to LSD due to receptor site variance) tastes metallic. Metallic taste, numb tongue if held in mouth, no effect if immediately swallowed and not orally absorbed? NBOMe. Bitter Metallic taste, no numb tongue, Works if swallowed and not held in mouth? most prob DOC, DOX, some psychedelic PEA. Likely active at single mg doses or less. You don't want to take a 5 mg tab of DOC (mind they were kind of large lol) if your expecting it to be a single dose of LSD.
Worst mistaken trip? Well I thought it was LSD. Took it, it had a bitter taste. Swallowed thinking it was DOM or similar. Well it was similar but worse, numb extremities, racing heart, headfuck. I took it at 5 pm and I was still effected, unable to sleep, until 4 am on the second day. So 30 + hours roughly. I have a period of time I don't remember shit. I kind of remember threatening someone in their own home... nice house guest or what? I don't recall who drove but I'm pretty fucking sure I didn't. Probably lost 20 odd hours of my life during which I behaved like a Shitbag.
The original artworks the blotters are based off, some are worth a lot of $, surprisingly known as "blotter art".